Lisa Marie Presley, and more celeb transformations

Actress Uma Thurman had some doing double-takes at the premiere for "The Slap" on Monday, February 9. The actress, 44, plays a TV writer in the U.S. update of the Australian show.

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The transformation of Zach Galifianakis continued January 25 at the Screen Actors Guild Awards, where the actor was barely recognizable from years past. What a difference some pounds and some facial hair can make. He first started slimming down in 2013, when he decided to stop drinking.

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Kirstie Alley set out to lose 30 pounds in 2014, but she went above and beyond and lost 50. Alley, a paid spokeswoman for Jenny Craig, used the weight loss program to slim down over the past year. Although her size has fluctuated in the past, Alley assured "Today's" Matt Lauer on January 5 that "This time, it's different."

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When Renee Zellweger arrived at the 2014 Elle Women in Hollywood awards October 20, some people said they couldn't recognize her. Perhaps that's because the "Bridget Jones" star has spent less time in the public eye recently; her last film credit was in 2010. That should change soon: Zellweger's next film, "The Whole Truth," is due in 2015.

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Hip-hop artist Missy Elliott proved she can still work it as she flaunted a slimmed-down figure in October at the launch of designer Alexander Wang's line for H&M. Apparently, an autoimmune disorder is not slowing down the "supa dupa fly" producer, who tweeted a picture of herself in a workout cap that reads "You Can't Workout With Us" after performing at the runway show.

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"#RichKids of Beverly Hills" star E.J. Johnson lost 50 pounds in five weeks after undergoing gastric sleeve surgery. In September, he told People he is not setting a specific number in terms of his goal for weight loss.

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Tom Arnold has lost about 90 pounds since his first child was born in 2013, and he was looking quite thin at the 2014 South by Southwest festival. He'd actually lost the same amount of weight before but regained it when he didn't maintain healthier habits. After his son was born, he knew he needed to make a lasting change. "I saw that little baby, and I thought, 'I gotta stay alive for as long as possible,' " Arnold said. "That's a lifelong commitment."

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Jessica Simpson showed off a supersvelte look in a Weight Watchers ad released in February 2014. "I was so insecure -- I couldn't even believe what I weighed," Simpson told "Good Morning America." The singer/fashion mogul says she is feeling better than ever since giving birth to her second child.

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Christina Aguilera turned heads on the American Music Awards' red carpet for two years in a row. At the awards ceremony in 2013, Aguilera surprised onlookers by arriving in a skin-tight white gown with revealing cutouts, displaying a much different look than her voluptuous appearance at the 2012 event.